Apparatus and method for controlling the taste of coffee, and a coffee maker comprising the apparatus

ABSTRACT

An apparatus for controlling the taste of coffee, a method of controlling the taste of coffee and a coffee maker including the apparatus. The apparatus includes a control unit, configured to determine a target pH value of water corresponding to a desired coffee taste, and a corresponding adjustment control signal; and a pH adjustment unit, configured to adjust, in response to the adjustment control signal applied to the pH adjustment unit, the pH value of water to be fed into a brewing unit of a coffee maker to the target pH value. In accordance with embodiments of the present disclosure, the pH value of water to be fed to a brewing unit of a coffee maker may be adjusted for a desired coffee taste.

This application is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/EP2014/079490, filed on Dec.31, 2014, which claims the benefit of International Application No.14161182.2 filed on Mar. 21, 2014 and International Application No.PCT/CN2013/091051 filed on Dec. 31, 2013. These applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

Embodiments of the present disclosure generally relate to coffee making,and more particularly to an apparatus for controlling the taste ofcoffee, a method of controlling the taste of coffee, and a coffee makercomprising said apparatus.

BACKGROUND OF THE INVENTION

Currently, coffee manufacturers are making great efforts to optimizebrewing systems and offer coffee beans or grinds which are diverse intaste, so as to enable fast and convenient coffee making providingcoffee of various tastes. Moreover, many coffee makers have been testedfor their coffee tastes and have been certified by authorities.Therefore, the coffee making machines may comprise a logo saying forexample “Certified by Italian Tasters”. However, these taste tests areperformed under controlled parameters and in practice it is difficultfor consumers to obtain the desired coffee taste because coffee makersmight be used in various environments with various parameters. Thismeans that a coffee maker might produce coffee with different tasteseven if it is used with the same coffee beans.

For example, as one of most important ingredients of coffee, waterusually has very different properties in different locations through theworld. Moreover, even if it is suggested to brew coffee with pure wateror bottled water, many coffee drinkers still trust the quality of tapwater and use it to brew coffee. These differences might result incoffee having different tastes.

In addition, although the coffee makers could brew coffee whose taste isrecommended or considered as the best by experts, consumers always havetheir own coffee drinking habits. As a matter of fact, different peopleusually have different coffee taste preferences. For example, somepeople would prefer stronger coffee while others prefer milder coffee;some people like stronger coffee in the morning and milder coffee in theafternoon while other people have other preferences. Thus, the samecoffee, even if it is highly recommended by experts, cannot satisfy allcoffee drinkers.

SUMMARY OF THE INVENTION

To this end, in the present disclosure, there is provided a solutionenabling controlling the taste of coffee so as to obviate or at leastpartially mitigate at least part of the above problems.

In a first aspect of the present disclosure, there is provided anapparatus for controlling the taste of coffee. The apparatus comprises acontrol unit and a pH adjustment unit. The control unit is configured todetermine a target pH value of water corresponding to a desired taste ofcoffee and a corresponding adjustment control signal. The pH adjustmentunit is configured to adjust, in response to the adjustment controlsignal applied to the pH adjustment unit, the pH value of water to befed into a brewing unit of a coffee maker to the target pH value.

In a second aspect of the present disclosure, there is provided a methodof controlling the taste of coffee. The method comprises determining atarget pH value of water corresponding to a desired taste of coffee anda corresponding adjustment control signal; and adjusting, in response tothe adjustment control signal, the pH value of water to be fed into abrewing unit of a coffee maker to the target pH value.

In a third aspect of the present disclosure, there is further provided acoffee maker comprising an apparatus for controlling the coffee tasteaccording to the first aspect of the present disclosure.

In accordance with embodiments of the present disclosure, the pH valueof water to be fed to a brewing unit of a coffee maker may be adjustedto achieve a desired coffee taste. In such a manner, the influence ofwater properties on the taste of coffee may be greatly decreased, andthus it is possible to make coffee with the same desired taste even whenwater with different properties is used.

Other features and advantages of embodiments of the present disclosurewill also be apparent from the following description of specificembodiments when read in conjunction with the accompanying drawings,which illustrate, by way of example, the principles of embodiments ofthe present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are presented in the sense of examples andtheir advantages are explained in greater detail below, with referenceto the accompanying drawings throughout which like reference numbersrepresent same or similar components and wherein:

FIG. 1 illustrates a schematic diagram of controlling the taste ofcoffee according to an embodiment of the present disclosure;

FIG. 2 illustrates a block diagram of an exemplary apparatus forcontrolling the taste of coffee according to an embodiment of thepresent disclosure;

FIG. 3 illustrates a schematic diagram of exemplary example factors thatcan be used in pH target value determination according to an embodimentof the present disclosure;

FIGS. 4A to 4D illustrate an example relationship between pH values andthe tastes of coffee according to an embodiment of the presentdisclosure;

FIG. 5 illustrates a diagram of solubility of CaCO₃ in water withdifferent pH values;

FIG. 6 illustrates a diagram of an exemplary schematic architecture of acoffee maker which comprises a pH adjustment unit according to anembodiment of the present disclosure;

FIG. 7 illustrates a schematic diagram of an exemplary pH adjustmentunit according to an embodiment of the present disclosure;

FIGS. 8A and 8B illustrate schematic diagrams of the operating principlefor pH value adjustment according to an embodiment of the presentdisclosure;

FIGS. 9A and 9B illustrate the carrying out of a pH value adjustmentaccording to an embodiment of the present disclosure;

FIG. 10 illustrates a schematic diagram of ion exchange for coffeebrewing according to another embodiment of the present disclosure;

FIGS. 11A and 11B illustrate schematic diagrams of exemplary ionexchange resins that can be used in the present disclosure;

FIG. 12 illustrates a schematic diagram of an exemplary preparation ofan ion exchanger according to an embodiment of the present disclosure;

FIG. 13 illustrates the influence of water on the crema volume index(CVI) according to an embodiment of the present disclosure;

FIG. 14 illustrates the influence of water on the pH value of brewedcoffee according to an embodiment of the present disclosure; and

FIG. 15 illustrates a flowchart of an exemplary method of controllingcoffee taste according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. It should beappreciated that, although the specification contains many specificimplementation details, these details are not to be construed aslimitations on the scope of any(?) invention or of what may be claimed,but rather as descriptions of features that may be specific toparticular embodiments of particular inventions. Certain features thatare described in this specification in the context of separateembodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable sub-combination. Moreover,although features may be described hereinabove as acting in certaincombinations and may even initially be claimed as such, one or morefeatures of a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asub-combination or variation of a sub-combination.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the/said [element,device, component, means, step, etc]” are to be interpreted openly asreferring to at least one instance of said element, device, component,means, unit, step, etc., without excluding a plurality of such devices,components, means, units, steps, etc., unless explicitly statedotherwise.

Hereinafter, reference will be made to FIGS. 1 to 14 to first describean apparatus for controlling coffee taste and a coffee maker comprisingthe apparatus according to an embodiment of the present disclosure.

Reference is first made to FIG. 1, which illustrates a schematic diagramof controlling the taste of coffee according to an embodiment of thepresent disclosure. As illustrated, in a coffee maker, there is a newlyadded apparatus 102 for controlling the taste of coffee, which can treatwater 101 to be used in a brewing unit 106, particularly by adjustingthe pH value of the water, so that the water is suitable to achieve adesired coffee taste. The treated water is then fed to a brewing unit106. On the other hand, coffee beans 104 are also fed to the brewingunit 106 after being ground in grinding unit 105. In the brewing unit106, coffee is made in a brewing process using treated water and groundcoffee beans. After the brewing process is completed, a coffee beverage107 is obtained which is ready for drinking.

Additionally, the apparatus 102 may also be used for another purpose,for example descaling, as denoted by 103. It may be appreciated thatcontrolling the taste of coffee is carried out by treating water throughpH adjustment thereof, which may also be used for descaling. Therefore,in an embodiment of the present disclosure, the apparatus 102 may alsobe used to treat water so as to descale the coffee maker in rinsingcycles.

As mentioned hereinabove, water has very different properties indifferent locations all over the world, which might substantiallyinfluence the taste of coffee. For example, in Europe, pH values ofwater vary from less than 4.5 to more than 8.5. However, in existingcoffee machines hardly any measures are taken to control the water sothat it is suitable for brewing. For one thing, the choice of the waterused is left to the end user, and for another thing, coffee makermanufacturers have limited influence on the choice of water. In some ofthe existing coffee machines, only for the purpose of descaling, thereare provided Brita filters to remove contaminants from the water andsoften the water, thereby reducing scaling. Thus, in fact, the existingcoffee makers do not take into account at all the impact of water on thetaste of coffee. Precisely in view of this, in embodiments of thepresent disclosure, there is proposed a solution for controlling thetaste of coffee by adjusting the pH value of water to be fed to abrewing unit of a coffee making machine.

Next, reference will be made to FIG. 2 to describe an exemplaryapparatus for controlling the taste of coffee according to an embodimentof the present disclosure. As illustrated in FIG. 2, the apparatus 102includes a control unit 102 a and a pH adjustment unit 102 b. Thecontrol unit 102 a is configured to determine a target pH value of watercorresponding to a desired coffee taste and a corresponding adjustmentcontrol signal. The control unit 102 a may be in the form of an embeddedmicroprocessor or any other appropriate processor or controller that issuitable to be used in a coffee maker. Then, the determined adjustmentcontrol signal will be provided to the pH adjustment unit 102 b, whichis configured to adjust, in response to the adjustment control signalapplied thereto, the pH value of water to be fed into a brewing unit ofa coffee maker to the target pH value.

In practice, the control unit 102 a may determine the target pH value ofwater corresponding to a desired coffee taste, based on many relevantfactors. Hereinafter, only for the purpose of illustration, FIG. 3illustrates a schematic diagram of several exemplary factors that couldbe used in pH value determination according to an embodiment of thepresent disclosure. However, it should be appreciated that the presentdisclosure is not limited to these factors as given in FIG. 3, and theperson skilled in the art might conceive other factors that could alsobe used in pH value determination from the teachings provided therein.

As illustrated in FIG. 3, the control unit 102 a may determine thetarget pH value of water based on, for example, professional tasteevaluation A1. That is to say, for taste control, it may define areference PH for a reference taste of coffee. The reference taste ofcoffee may be a recommend taste or an optimal taste which is determinedby experts through professional taste evaluation. Through professionaltaste evaluation, there may also be provided a relationship between pHvalues and the tastes of coffee. The relationship may be generated basedon information provided by experts performing the professional tasteevaluation and stored by manufacturers in the memory of the coffeemaker. The relationship may be a reference pH value or a reference pHvalue range corresponding to different tastes of coffee. For example,the experts could recommend reference pH values or ranges respectivelyfor different kinds of coffee.

FIGS. 4A to 4D illustrate an example relationship between pH values andtastes of coffee according to an embodiment of the present disclosure,which is obtained through professional taste evaluation. Specifically,FIG. 4A illustrates the relationship between the pH values and scores(S) for sweetness; FIG. 4B illustrates the relationship between the pHvalues and scores (S) for aftertaste; FIG. 4C illustrates therelationship between the pH values and scores (S) for acidity; and FIG.4D illustrates the relationship between the pH values and scores (S) foraroma. As illustrated in FIGS. 4A to 4D, for different coffee tasteproperties, the optimal pH values are different. Based on the aboverelationships for a reference taste, it is possible to determine thetarget pH value of water corresponding to a certain taste of coffee. Insuch a manner, the pH value can be controlled so as to obtain the targetvalue in order to deliver the recommended taste that is considered to beideal by experts. Hence, the present disclosure enables a consistenttaste for a certain kind of coffee to be obtained.

Besides, the target pH value may also be determined based on customerpersonal preference A2 regarding coffee taste properties or waterproperties. For example, in the coffee maker, there may be provided someoptions which can be activated by means of a user interface, so that thecustomer can input his/her own preference. The user interface couldinclude, for example, a touch display device, a LCD device incombination with buttons, which is used to display coffee tasteproperties or water properties and provide an interactive interface tothe customer. The use of an LCD may provide the customer with a visualdisplay. Or, alternatively, the coffee maker may be provided with a moreabstract representation as the user interface, e.g. numerical scales,wheels with colors for representing different coffee taste properties,etc. Such an abstract representation will allow the consumer to make aconsistent choice. Thus, it may be appreciated that the selecting ofcoffee taste properties or water properties may be performed either in adiscrete way or in a continuous way.

The coffee taste properties presented by a user interface may include,for example, bitterness, sweetness, acidity, aroma and so on. Therefore,through the user interface, the customer may select coffee tasteproperties based on his/her own preference. Different coffee tasteproperties correspond to different target values and thus the customer'sselection will result in a change of the water properties. Based on thecustomer's choice, the control unit 102 may map the target pH valuecorresponding to the coffee taste selected by the customer. For example,it may use information from professional taste evaluation A1, whichgives the relationship between pH values and coffee taste or coffeetaste properties, to link the customer's selection to the target pHvalues.

Besides, the user interface may also directly present options regardingwater properties, such as pH value of the water. The user interfacecould allow consumers to make a choice in a number of ways, such asexplicitly choosing the pH of the water, choosing the pH based onexample cities (e.g. in European countries, Asian countries). In thiscase, the range of possible pH values may be mapped to the userinterface input so that the customer can make a choice according tohis/her taste preference. In such a way, for example, the control unit102 a may receive the customer's selection from the interface anddirectly map the selection to a corresponding pH value, which will betaken as the target pH value.

Furthermore, other information such as coffee drinking habits, personalphysical condition may also be considered. This information may alsohelp to determine or modify suitable coffee taste properties for thecustomer automatically and then map them to a corresponding pH value orrange. These relationships may be provided by manufacturers.

It may be appreciated that, in practice, the consumer's preference maydeviate from the expert reference and vary greatly according to regionaland personal preference. However, with embodiments of the presentdisclosure, consumers may be enabled to control the taste of coffeeaccording to their personal respective taste preference rather thanmaking a choice from coffee tastes recommended by experts. In such away, a personalized taste control may be achieved.

Additionally, the apparatus 102 may also comprise a sensor configured tosense properties A3 of coffee beans or grinds. And, in turn, the controlunit 102 a may be configured to determine the target pH value of waterbased on the sensed properties A3 of coffee beans or grinds. It may beappreciated that for different kinds of coffee, particularly differentproperties A3 of coffee beans or grinds, such as bean type, bean origin,roasting degree and so on, the suitable pH value of water may bedifferent. Based on the sensing results from the sensor, the controlunit may determine a suitable pH value as the target value. In practice,the actual pH value that is suitable for brewing with respect to certainproperties of beans may be defined by the manufacturers. It should beappreciated that the factor A3 may be used separately or in combinationwith one or more other factors, such as professional taste evaluationA1, customer personal preference A2 and so on.

Additionally, frequent brewing with for example tap water will cause ascaling problem within the coffee maker. Normally, descaling is achievedby adding a special solution, such as water softeners like vinegar, tothe water to create acid water. Current coffee makers usually requirethe customer to measure the properties of the local water before usingthe coffee maker and then program the device accordingly through a userinterface. Then, based on the number of cups brewed, the deviceindicates to the customer that it needs to be descaled. Although watersofteners have the advantage that they can easily solve the scalingproblem, their use involves another issue that cannot be ignored, i.e.,the coffee taste deterioration. Water softeners usually consist of a bedof ion exchange resins that trap calcium ions and replace them withsodium ions. However, the extra sodium ions change the properties of theoriginal water, which might adversely influence the taste of coffee.

To tackle the scaling issue, the control unit 102 a may also determine adescaling target pH value of water based on at least one of the hardnesssetting of the water and the treatment efficiency A4, so as to descalethe coffee maker in a rinsing cycle. That is to say, the control unit102 a may also control the pH adjustment unit for descaling. Based onthe hardness setting of the water and the treatment efficiency, thecontrol unit 102 a may determine the descaling target pH value. Forexample, the amount of coffee that has been served, for example thenumber of cups, may be recorded. Thus, when the predetermined amount ofcoffee is reached, descaling may be performed by treating the water to atarget descaling pH value during a rinsing cycle. In such a way, thebuildup of scale in the coffee maker can be prevented. FIG. 5 shows adiagram of the solubility of CaCO₃ (mol/L) in water with different pHvalues. From the plot it can be seen that water with a lower pH maysolubilize more CaCO₃, i.e. the acid water is helpful for descaling.Thus, it is feasible to descale the coffee maker in a rinsing cycle byadjusting the pH value of the water. When the rinsing cycle iscompleted, the treated water will be discharged as waste water.

On the other hand, it is also possible to descale in a continuous way.That is to say, descaling may be performed each time coffee is made. Forexample, it is possible to first adjust the pH value of water to atarget descaling pH value to descale the coffee maker, before adjustingthe pH value to the target pH value corresponding to the desired taste.In such a way, the scale formed may be removed before coffee is brewed.The treated water will be discharged as waste water. In addition, it isalso feasible to descale the coffee maker after coffee is brewed.Moreover, it may be appreciated that periodical descaling requires alower pH (more acidic) solution than continuous descaling, since acertain amount of scale deposit has already accumulated before a rinsingcycle.

After the pH target value is determined, the control unit 102 a maydetermine the corresponding adjustment signal to be applied to the pHadjustment unit. The pH adjustment signal may be determined based on thetarget pH value and the initial pH of the water. The initial pH valuemay be obtained through a sensor for detecting the incoming water or itmay be provided by the customer who manually measures the pH value ofthe water. The pH adjustment signal may be, for example, the voltage tobe applied to the pH adjustment unit 102 b. In such a case, based on thetarget pH value and the initial pH of the water, the pH adjustmentsignal may be mapped onto a voltage polarity and amplitude as the pHadjustment signal for a certain flow rate of water. Besides, pHadjustment is also possible by applying current to the pH adjustmentunit 102 b. Alternatively or additionally, the pH adjustment signal maybe also a signal for controlling the flow velocity in the pH adjustmentunit 120 b. The determination of the pH adjustment signal will bedetailed hereinbelow with reference to FIGS. 6 to 9B.

Hereinafter, an exemplary arrangement of the apparatus 102 in a coffeemaker will be described with reference to FIG. 6, which shows a diagramof an exemplary schematic architecture of a coffee maker which comprisesa pH adjustment unit 102 b according to an embodiment of the presentdisclosure. As to the control unit 102 a, it may be appreciated that itmay be a controller which is separate from a processor which is alreadypresent in a coffee maker or which is not already present in a coffeemaker. That is to say, to implement the present invention, a newprocessor may be added or the original processor may be reused.

As illustrated in FIG. 6, water 101 enters into a water tank 110, andthe water will be pumped and fed through pipes 120 a, 120 b, 120 c and120 d to a valve 112 and a solenoid valve 113 by a pump 111. When thevalve 112 is opened, the water will flow, through a pipe 120 f, into thepH adjustment unit 102 b in which the water is treated. In the meantime,when the solenoid valve 113 is opened, the water will flow into a boiler114 in which the water is heated. In the pH adjustment unit 102 b, thepH value of the water will be adjusted to the target pH value and thewater with the target pH value will in turn be fed to a heat exchanger115. In the heat exchanger 115, heat exchange will take place betweenthe water contained in the heat exchanger 115 and steam and watercontained in the boiler 114. Or, in other words, the water contained inthe heat exchanger 115 will be heated by steam and hot water containedin boiler 114. After that, the heated water contained in the heatexchanger 115 will be further fed to the brewing unit of the coffeemaker, especially to the brewing head, through pipe 120 h. Steam in theboiler 114 will be provided to the steam valve through pipe 120 i, andthe steam may be used to froth milk while hot water in the boiler 114may flow into pipe 120 j and finally flows back into a pressurereduction valve through pipe 120 k.

It should be appreciated that the pH adjustment unit 102 b could be alsointegrated into the water tank 110 to control the properties of thewater in the tank. In this case, it would be required to adjust thewater properties of all the water in the tank each time. In addition, itis also possible to arrange the pH adjustment unit at any other positionbetween the heat exchanger 115 and the water tank 110, for exampledownstream of the pump 111. However, it may be appreciated that thepreferred solution is to get the required amount of water from the tankand then adjust the properties of the water to the required pH value.

The pH adjustment unit 120 b can use conventional water electrolysistechnologies to adjust the pH of water. The electrolysis-based approachapplies electric power to decompose water into O₂ and H₂ and at the sametime leave OH⁻ and H⁺ in the water. The chemical change can be expressedby the following expressions (1) and (2):2H³⁰ +2e⁻→H₂(Cathode)  (1)4OH⁻−4e⁻→2H₂O+O₂(Anode)  (2)

Therefore, the pH value of water can be changed so as to obtain alkalinewater or acidic water. However, the disadvantage of this technology isthat unwanted waste water will be generated.

In preferred embodiments of the present disclosure, the uni-directional(Uni-D) pH adjustment technology may be used, which is based on apseudo-faradic reaction. Hereinafter the pH adjustment unit based on theUni-D pH adjustment technology will be described in detail withreference to FIGS. 7 to 9B.

Next, reference is first made to FIG. 7, which is a schematic diagram ofan exemplary pH adjustment unit according to an embodiment of thepresent disclosure. As illustrated in FIG. 7, the adjustment unit 120 bmay include water container 701, an electrode 702 and an electrode 703as a counter electrode. The water container 701 is configured to receivewater to be electrolyzed via a water inlet 704 and discharge treatedwater via a water outlet 705, or in other words water 101 will enterinto the water container through the water inlet 704 and beelectrolyzed, and then the treated water 101′ will be dischargedtherefrom via the water outlet 705. However, it should be appreciatedthat both the water inlet 704 and the water outlet 705 are schematicallyshown only for the purpose of illustration, and the present disclosureis not limited to the specific locations and/or forms as illustrated inFIG. 7.

The two electrodes 702 and 703 are arranged face to face in the watercontainer 701, and one of them acts as an anode and the other acts as acathode. The two electrodes 702 and 703 are connected to a power supply(not illustrated) such as a DC power supply, which is controllable bythe controller unit 102 b and which is configured to provide therequired pH adjustment control signal under control of the control unitto achieve a desired pH value. For example, the electrode 702 may beconnected to a positive pole of the power supply and the electrode 703to a negative pole of the power supply. The electrode 702 can be madefrom for example Ti, Pt, Au or any other inert metal or oxide thereofsuch as TiMMO (Titanium Mixed Metal Oxide). The electrode 22 can be madefrom, inter alia, active carbon.

FIGS. 8A and 8B illustrate schematic diagrams of the operating principleof a pH adjustment unit according to an embodiment of the presentdisclosure, wherein the electrode 702 is for example a TiMMO electrodeand the electrode 703 is for example an active carbon electrode. First,in a case illustrated in FIG. 8A, the electrode 702 made from TiMMO actsas the anode and the electrode 703 made from active carbon material actsas a cathode. During the electrolysis process, a pseudo-faradic reactiontakes place at the anode, whereby the oxidation status of the transitionmetal is increased. The anode loses electrons, and anions in thesolution are absorbed by TiMMO, wherein the hatched area schematicallyshows an electrochemical ion absorption reaction. Or in other words,H+ions in the water 101 that is fed into the water container areconsumed by collecting the electrons at the cathode while OH− ions inthe water are not consumed at the anode and are left in the water. Thisbreaks the original balance between H+ and OH−, and thus the pH value ofthe solution is increased and alkaline water 101′a is obtained.

On the other hand, as illustrated in FIG. 8B, the electrode 702 madefrom TiMMO acts as the cathode and the electrode made from active carbonmaterial acts as the anode. In the pH adjustment unit, a pseudo-faradicreaction at the cathode takes place, whereby the oxidation status of thetransition metal is lowered, together with absorption of cations intothe lattice of TiMMO, wherein the hatched area schematically shows anelectrochemical ion absorption reaction. At or near the anode, OH⁻ ionsin water become oxidized by losing electrons (i.e., are oxidized),thereby producing H₂O and O₂. That is to say, OH⁻ ions in the water areconsumed while H⁺ ions remain in the water. Accordingly, the imbalancebetween H⁻ and OH⁻ causes the pH value of the solution to decrease andthus acid water 101′b is obtained.

FIGS. 9A and 9B illustrate performance of a pH adjustment unit accordingto an embodiment of the present disclosure. From plots as given in thesefigures, it can be seen that the pH adjustment performance is dependenton electrolysis time and current/voltage. The longer the water is incontact with the electrodes, the more OH³¹ anions or H⁻ cations(depending on whether the TiMMO electrode acts as anode or cathode) aregenerated, which means a lower or higher pH could be achieved. On theother hand, increasing the current/voltage will increase the electrontransfer speed between electrodes and the water, and thus the generationrate of OH⁻ or H⁺ ions in the water may be increased accordingly.Besides, although not illustrated, it may also be appreciated that theflow rate of water also has a substantial effect on the pH adjustmentperformance. Generally, the larger the flow rate, the shorter the timethe water will be in contact with the electrode, and thus the smallerthe numbers of H⁺ or OH⁻ ions produced, and vice versa.

Using the Uni-D pH adjustment unit according to embodiments of thepresent disclosure, pH adjustment may be efficiently achieved and at thesame time said adjustment unit will not generate any undesirable wastewater.

Besides, in some embodiments of the present disclosure, to improve thetaste of coffee, especially for espresso coffee, the apparatus 102 mayfurther comprise an ion exchanger to increase the amount of crema. As isknown, the crema is one of the most important components for espressocoffee and its volume and texture greatly influence a coffee drinker'sfirst impression. The crema volume index is used to quantify the amountof crema which usually can be represented by the ratio of crema volumeto total liquid volume. In addition to the crema, coffee acidity isanother critical parameter to evaluate the taste of coffee. Generally,the resulting crema volume index of coffee made by an existing coffeemaker is lower than 10%, which is much lower than the minimum value ofthe crema volume index for a perfect crema. Herein, there is furtherprovided a solution by means of which the amount of crema may beincreased through ion exchange.

FIG. 10 is a schematic diagram of ion exchange for coffee brewingaccording to another embodiment of the present disclosure. Asillustrated in FIG. 10, water 1001 will be fed to the ion exchanger 1002in which the water will be treated through anion ion exchange so thatthe treated water is abundant in bicarbonate ions which could be a maincomponent of the crema. Then, the treated water is fed to a heatingsystem 1003 to be heated and subsequently to the brewing unit 1006.Meanwhile, coffee beans 1004 will be fed to and ground in the grindingunit 1005, and after that the ground coffee beans will be fed to thebrewing unit 1006. In the brewing unit 1006, the coffee will be brewedwith treated water and the ground coffee beans. After the brewingoperation, the coffee 1007 is ready. Due to abundant bicarbonate ions inthe treated water, more crema will be generated in the coffee brewingprocess. Therefore, the resulting crema volume index may be improvedgreatly. In addition to the anion exchange relating to bicarbonate ions,the cation exchange may also be performed so as to exchange hardnesscations (such as Ca²⁺, Mg²⁺, or the like) contained in water, which mayresult in scaling issues, for beneficial cations (such as Na⁺, K⁺ and soon), which are beneficial to the human body and which do not result inscaling issues. In such a way, the descaling problem may be alleviatedat the same time as well.

In embodiments of the present disclosure, ion exchange resins foranion-ion exchange and cation-ion exchange may be separate resins. Forexample, as illustrated in FIG. 11A, cation exchange resin 1002A withcounter ions of Na⁺ or K⁺ may be used for removing hardness ions such asCa²⁺, Mg²⁺, or the like. Anion exchange resin 1002B with counter ions ofHCO₃ ⁻ is used for absorbing anions such as Cl⁻, SiO₄ ²⁻, PO₄ ²⁻ andreleasing bicarbonate ions into the water. Alternatively, as illustratedin FIG. 11B, the ion exchange resins could also be amphoteric ionexchange resins 1002C, which contain positive groups and negative groupson the polymer chain simultaneously, such as ion retardation resin DOW11A8.

FIG. 12 shows in a schematic diagram an exemplary preparation of an ionexchanger according to an embodiment of the present disclosure. Cationexchange resins with Na⁺ counter ions as denoted by 1002A may be used,which are commercially available. The original anion exchange resins maybe Cl⁻-type. Before use, they may be immersed in saturated bicarbonatesolution such as NaHCO₃ solution, KHCO³ solution, etc, for hours, so asto exchange all Cl⁻ ions in the resins for HCO₃ ⁻. In such a way, anionexchange resins with HCO₃ ³¹ ions can be obtained. After that, the twotypes of resins may be mixed in proportion and finally bi-ion resins areobtained (1002A+B). Finally, the mixed resins are piled in a container1002D, which comprises a water inlet 1002E and a water outlet 1002F. Thewater to be fed to the brewing unit may be introduced into the container1002D via the water inlet 1002E; in the container, the ion exchange willbe performed and then the water will be discharged from the container1002D through water outlet 1002F after being treated. Generally, thetreatment of the fed-in water might take several minutes, which dependson the water flow rate. For example, a test shows that, if a flow rateof 100ml/min is set, 500 ml of treated water will have been preparedafter 5 minutes, which is available to brew at least 4 shots ofespresso.

Besides, it may be understood that water, such as tap water, oftencontains hardness ions, calcium ions, magnesium ions, chlorine ions,sulphate ions, silicate ions, phosphate ions and so on, but after thetreatment, all anions may be replaced by carbonate ions and at the sametime, these hardness ions such as Ca²⁺, Mg²⁺ are replaced bymono-covalent ions, such as Na⁺. That is to say, more beneficial ionsare present and the treated water is much more suitable for coffeebrewing. Due to the decrease in hardness ions, such as Ca²⁺ and Mg²⁺,there is a lower risk that the heater is subject to scaling issues, anddue to the fact that the HCO₃ ⁻ content in treated water is higher,espresso coffee with a higher volume of crema may be produced duringextraction of coffee flavor compounds from the coffee powders by usingthe heated water.

The inventors have done experiments on four exemplary types of waterprepared for brewing espresso and the properties of each type of waterare listed in Table 1. Table 1 Properties of water samples

Temporary hardness Hardness EC Water (°dH) (°dH) (s/cm) pH W1 6 13 4918.07 W1_treated 14 <1 445 7.4 W2 10 20 614 7.53 W2_treated 17 <1 6017.47In the Table, water W1_treated and W2_treated is water obtained bytreating water W1 and W2 through cation and anion exchange as proposedin the present disclosure. Compared to water W1 and W2, the temporaryhardness (indication of bicarbonate ions) of water W1_treated andW2_treated is increased substantially; the hardness of water W1_treatedand W2_treated is decreased to less than 1; the electric conductivity ofwater W1_treated and W2_treated is decreased slightly due to the weakerelectric conductivity of bicarbonate ions; the pH of water W1_treatedand W2_treated is slightly decreased because of the absence of phosphateions, silicate ions that lead to higher pH values.

The water samples were each used to brew espresso coffee. Here, Illycoffee beans (medium roasted) were used. After brewing, the crema volumewas recorded, the pH of the brew was tested. FIG. 13 and FIG. 14respectively illustrate the recorded crema volume index (CVI) and the pHtest value. From FIG. 13, it is clear that water with a larger amount ofbicarbonate ions produces more crema. Specifically, the crema volumeindex of W1 increased to about 12% after the treatment, and the crema ofW2 increased to about 15% after the treatment. From FIG. 14, wherein thehatched area denotes the optimal pH range of the coffee brew, it may beseen that the brew pH values for all four types of water are within thisoptimal range, and the treatment by ion exchange nearly had no influenceon the taste of coffee, such as coffee acidity.

Hereinafter, descriptions are given mainly of embodiments of apparatusas provided in the present disclosure, and next reference is made toFIG. 15 to describe the method of controlling the taste of coffeeaccording to an embodiment of the present disclosure.

As illustrated in FIG. 15, at step S1501, there may be determined atarget pH value of water corresponding to a desired coffee taste and acorresponding adjustment control signal. In an embodiment of the presentdisclosure, the target pH value of water may be determined based on aprofessional taste evaluation (A1), particularly the relationshipbetween pH values and coffee tastes provided through the professionaltaste evaluation. For example, the taste of the coffee to be made willbe recommended by experts and thus the target pH value will bedetermined as the pH value which is considered to be optimal for thecoffee taste by the experts, so that it is possible to ensure aconsistent taste for a certain kind of coffee. Additionally, oralternatively, the target pH value of water may also be determined basedon customer personal preference (A2), especially regarding coffee tasteproperties or water properties. The customer may select his ownpreference through the user interface provided on the coffee maker. Thecustomer's selection may be mapped to a target value or may be linked tothe professional taste evaluation, which will in turn map to acorresponding pH value. Therefore, it is possible to implement apersonalized taste control. Moreover, the coffee maker may further senseproperties of coffee beans or grinds at step S1503. In such a case,additionally or alternatively, the target pH value of water may befurther determined based on the sensed properties of coffee beans orgrinds. Thus, by determining the target pH value, the differentproperties of coffee beans or grinds may be considered, thus providing afurther possibility to make a desired cup of coffee. Based on thedetermined target value, a corresponding adjustment control signal maybe determined, which may be a polarity and amplitude of thecurrent/voltage and/or the flow rate of water.

Then, at step S1502, in response to the adjustment control signal, a pHvalue of water to be fed into a brewing unit of a coffee maker may beadjusted to the target pH value. The pH adjustment may be performedbased on conventional electrolysis technology. Or, alternatively, the pHadjustment may be performed based on Uni-D pH adjustment technology,which will not generate any undesired waste water.

Besides, a descaling pH target value of water may be further determinedbased on at least one of the hardness setting of the water and thetreatment efficiency so as to descale the coffee maker in a rinsingcycle or in a continuous way at step S1504. In such a way, the scalingproblems may also be addressed.

In addition, to produce more crema, at step S1505, anions present in thewater to be fed to the brewing unit of the coffee maker may be exchangedfor bicarbonate ions by ion exchange resins. Particularly, the ionexchange resins are prepared by immersing anion exchange resins insaturated bicarbonate solution. At the same time, cations contained inthe water may also be exchanged for beneficial cations by the ionexchange resins or additional ion exchange resins at step S1506. In sucha way, more crema may be produced in the coffee making process and inthe meantime the scaling problem may be addressed as well.

Hereinbefore, the method as proposed in the present disclosure has beenbriefly described, however it may be appreciated that detailedoperations in the method correspond to operations of apparatus asprovided with reference to FIGS. 1 to 14, and thus for details regardingthe method as proposed herein, reference may be made to the descriptionwith reference to FIGS. 1 to 14.

Besides, it may be understood that the ion exchanger 1002 may becombined with the coffee control apparatus 102, for example locateddownstream or upstream of the pH adjustment unit 102 b of the apparatus,but this is not to be construed in a limiting sense and it is alsopossible to perform the ion exchange individually as a separatesolution. Additionally, although the crema has been described as one ofthe most important evaluation indicators for espresso coffee, the ionexchange as proposed in the present disclosure is not limited only toespresso coffee but may also be performed whenever the customer wantsmore crema. For example, the user interface could provide an option formore crema; if the customer selects more crema, the ion exchange may beperformed; otherwise, the ion exchange may not be performed. This couldbe implemented by providing a bypass pipe without an ion exchanger andtwo valves for controlling the water so as to flow through either thebypass pipe or the pipe with the ion exchanger.

In addition, it may be appreciated that factors as given in FIG. 3 maybe used separately or in combination with each other in any proper form.Moreover, it is possible to add other factors which are different fromthose given in FIG. 3, or it is also possible to use fewer factors indetermining the target pH value, depending on the requirements of theapplications.

Therefore, it is to be understood that the embodiments of the disclosureare given only for the purpose of illustration and the presentdisclosure is not to be limited to the specific embodiments disclosedherein. Modifications and other possible embodiments are intended to beincluded within the scope of the appended claims.

The invention claimed is:
 1. An apparatus for controlling a taste ofcoffee, the apparatus comprising: a coffee maker brewing unit forbrewing coffee, a pH adjustment unit and a control unit, the controlunit, configured to: receive a desired taste of coffee from a userinterface; map the desired coffee taste to a corresponding one of aplurality of target pH values of water, wherein the mapped target pHvalue of water is determined based on a mapped relationship between theplurality of target pH values and corresponding coffee tastes, andwherein each one of the plurality of target pH values of watercorrespond to a different predefined coffee taste; and determine acorresponding adjustment control signal based on the mapped target pHvalue; and the pH adjustment unit, configured to adjust, in response tothe adjustment control signal applied to the pH adjustment unit, a pHvalue of water to be fed into the coffee maker brewing unit to themapped target pH value by adjusting one or more of a voltage or acurrent of the pH adjustment unit or a flow velocity of the water in thepH adjustment unit.
 2. The apparatus according to claim 1, wherein thecontrol unit is further configured to determine the mapped target pHvalue of water based on a customer personal preference setting regardingcoffee taste properties or water properties.
 3. The apparatus accordingto claim 1, further comprising a sensor configured to sense propertiesof coffee beans or grinds and configured to produce a correspondingsensor signal, wherein the control unit is further configured todetermine the mapped target pH value of water based on the correspondingsensor signal.
 4. The apparatus according to claim 1, wherein thecontrol unit is further configured to determine a descaling target pHvalue of the water, based on a hardness setting of the water and a timeit takes the pH adjustment unit to adjust the pH value of the water, todescale the coffee maker.
 5. The apparatus according to claim 1, furthercomprising an ion exchanger including a container and ion exchangeresins present in the container, wherein the ion exchange resins areconfigured to exchange anions contained in water to be fed to thebrewing unit of the coffee maker for bicarbonate ions, and wherein theion exchange resins are prepared by immersing anion exchange resins insaturated bicarbonate solution.
 6. The apparatus according to claim 5,wherein the ion exchange resins are further configured to exchangecations that cause scaling and that are contained in the water forcations that do not cause scaling.